TW200947142A - Surface shape measuring apparatus, exposure apparatus, and device manufacturing method - Google Patents

Abstract

A surface shape measuring apparatus includes an illumination system and a light receiving system. The illumination system splits wide-band light from a light source into measurement light and reference light, illuminates the measurement light to obliquely enter a surface of the film, and illuminates the reference light to obliquely enter a reference mirror. The light receiving system combines the measurement light reflected by the surface of the film and the reference light reflected by the reference mirror with each other and introduces the combined light to a photoelectric conversion element. An incident angle of the measurement light upon the surface of the film and an incident angle of the reference light upon the reference mirror are each larger than the Brewster's angle. S-polarized light and p-polarized light included in the measurement light entering a surface of the substrate have equal intensity on the photoelectric conversion element.

Description

200947142 VI. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to a surface shape measuring device and an exposure device. ~ [Prior Art] - Describes the prior art related to the surface shape measuring device and the exposure device using the former, and the semiconductor exposure device requiring high-accuracy surface shape measurement. When a microstructure semiconductor device or a liquid crystal display device is manufactured by using a photolithography (printing) technique, a projection exposure apparatus is used to project and transfer a circuit pattern drawn on a photomask (mask) to a crystal via a projection optical system. On the circle. In projection exposure apparatus, a semiconductor device of higher packing density results in the need to project a circuit pattern on the reticle to a wafer for exposure at a higher resolution power. The minimum critical dimension (resolution) that can be transferred in a projection exposure apparatus is proportional to the wavelength of the light used in the exposure, and is inversely proportional to the number of apertures (NA) of the projection optics. Therefore, set the exposure wavelength. For shorter turns, obtain higher resolution power. For this reason, the light source used in projection exposure equipment has recently been changed from ultra-high pressure mercury lamps (ie g-line (wavelength about 436 nm) or i-line (wavelength about 365 nm)) to KrF excimer laser (wavelength about 248). Nm) or ArF excimer laser (wavelength about 193 nm) that emits light of shorter wavelengths. Also consider the actual use of infiltration exposure. In addition, a wider exposure area is required. In order to meet these needs, the main exposure equipment consists of step-and-repeat type-5-200947142 (also known as "stepper"), in which a single exposure is used to reduce the size on the wafer. The squared exposed area is changed to a step_and-scan form (also referred to as a "scanner") in which the exposed area has a rectangular slit shape and can be compared by scanning the mask and the wafer at a high speed. Highly accurate exposure of large target areas. - in the scanner, during the exposure, at a predetermined position on the wafer, before the exposure slit region, the crystal at the predetermined wafer position is measured by the surface position detecting unit in the form of a light tilt-injection system The position of the circular surface (ie, the position in the direction of the optical axis of the projection optics, also known as the focus). Based on the measurement results, when the predetermined wafer position is exposed, a correction is made such that the wafer surface is aligned with the best focus position for exposure. In particular, a plurality of measurement points are set in the exposure slit region in the longitudinal direction of the exposure slit (the direction perpendicular to the scanning direction) to measure not only the height (focus) of the wafer surface position, but also the wafer. The surface is tilted. Many methods of measuring focus and tilt have been proposed. For example, Japanese Patent Publication No. 06-260391 and U.S. Patent No. 6,249,35, the disclosure of which is incorporated herein by reference. PCT Domestic Publication No. 2006-514744 proposes the use of a configured gas gauge sensor to spray air-to-wafer to the wafer and measure the wafer surface position. Another method of using an electrostatic capacitance sensor is also proposed. However, in recent years, due to the trend of shorter exposure light wavelengths and larger projection optical system NA, the depth of focus becomes very small, and the accuracy of aligning the surface of the wafer to be exposed with the best focal plane (so-called focusing) The need for precision has been raised to a higher level. In particular, even if the equivalent error measurement -6-200947142 is caused by the influence of the pattern on the wafer and the thickness variation of the photoresist applied on the wafer, the measurement error of the surface position detecting unit cannot be ignored. For example, due to the change in the thickness of the photoresist, a step height difference and a reticle 'i' which is close to the depth of focus are generated at a level close to the peripheral circuit pattern. Therefore, the tilt angle of the photoresist surface is increased by *, and in the reflected light detected by the surface position detecting unit, after being reflected or refracted, the reflected light from the rear surface of the photoresist is shifted by the specular reflection angle Φ . In addition, the reflectance between the dense region of the pattern and the rough region of the pattern is different due to the difference in density of the pattern on the wafer. Therefore, in the reflected light detected by the surface position detecting unit, the reflected angle and the reflected intensity of the reflected light from the rear surface of the photoresist are changed, and the waveform obtained by detecting the reflected light is detected. Become asymmetrical and produce measurement errors. Fig. 19 illustrates the case where the substrate SB is irradiated with the light metering MM. In the optical sensor proposed in Japanese Patent Laid-Open Publication No. 06-260391, the reflectance of the SB is different in different regions. In the case described, the measuring ray 0 MM is inclined at an A angle with respect to a boundary line between different reflectance regions, so that the measurement is performed in the direction indicated by α '. Figure 20 illustrates the intensity distribution of the reflected light at three mutually separated cross sections in the direction indicated by /3 ' _, i.e., the cross sections ΑΑ' ^ , : ΒΒ ' and CC'. The reflected light has good symmetry in the cross sections ΑΑ' and CC'. At a cross-section ΒΒ' comprising regions of different reflectivity, the reflected light has an asymmetrical profile. In other words, the barycenter of the reflected light is offset from the predetermined position and a measurement error is generated. Therefore, the waveform signal detected by receiving the reflected light becomes asymmetrical and the contrast of the detected signal waveform is significantly degraded 200947142, thus causing difficulty in accurately measuring the position of the wafer surface. This difficulty leads to large out-of-focus and wafer damage. As mentioned above, the intensity of the reflected light depending on the pattern on the wafer is altered by the interference caused by the reflected light from the front and back surfaces of the photoresist. Therefore, in some cases, it is difficult to accurately 'detect the position on the wafer surface by receiving the reflected light. *

Figure 23 illustrates the structure of a surface shape measuring apparatus disclosed in U.S. Patent No. 6,249,315. The disclosed surface shape measuring apparatus includes a light Q source 101, a lens 103, a beam splitter 105, a reference mirror 130, a beam combiner 17 in the form of a diffraction grating, a lens 171, a lens 173, and a photoelectric conversion element 175. In the surface shape measuring apparatus, the light system is obliquely irradiated to the sample 3 60, and the shape of the sample 3 60 is determined by the interference signal detected by the photoelectric conversion element 175. The light received by the photoelectric conversion element 175 includes light reflected from the front surface of the photoresist and light reflected from the rear surface of the photoresist. This improves the difficulty of accurately measuring the shape of the surface before the photoresist. Figure 21 illustrates the interference signal obtained in a conventional device, and Figure 23 illustrates the scanning of sample 3 60 by actuator 3 97 in the direction of the vertical sample surface. The interference signal in Figure 21 is obtained when the unpatterned sample on the wafer is equivalently measured, and the one illustrated in Figure 22 is obtained when only the photoresist is applied to the sample. _ because the received light includes not only the reflected light from the front surface of the photoresist but also the reflected light from the back surface of the photoresist, and the interference signal formed in this state is measured by the light from the photoresist The interference produced by the reflected light from the back surface affects the interference produced by the reflected light from the front surface of the photoresist in a superimposed manner. This results in the difficulty of accurately detecting the height information of the front surface of the photoresist using only the reflected light from the front surface -8 - 200947142 of the photoresist. In order to simultaneously measure the interference signals from the reflected light from the front and back surfaces of the photoresist, U.S. Patent No. 6,249,315 proposes to increase the front surface of the photoresist by increasing the angle of incidence of the substrate. The method of reflectivity. U.S. Patent No. 6,249,35, the disclosure of which is directed to the relative enhancement of the front surface of the photoresist from the substrate as compared to the reflected light from the back surface of the photoresist. Light. Q However, when the substrate is composed of A1 or Cu and has high reflectivity, the rear surface of the photoresist (ie, the photoresist/substrate interface) has a high degree of reflectivity, which makes it impossible to sufficiently suppress the reflection from the rear surface of the photoresist. The effect of light, even when the incident angle of light set on the substrate is large. Therefore, the error is caused by the flaw formed by measuring the front surface of the photoresist. In addition, when a gas gauge sensor is used as described in PCT Domestic Publication No. 2006-514744, the specific problem that fine particles mixed in the gas are also sprayed onto the wafer occurs, and cannot be operated under vacuum. The exposure apparatus Q, such as an EUV (Ultraviolet Light) exposure apparatus using ultra-ultraviolet light, uses a gas gauge sensor because the degree of vacuum is lowered by the sprayed gas. SUMMARY OF THE INVENTION According to one aspect of the present invention, a surface shape measuring apparatus can measure a surface shape with high accuracy without being affected by a reflectance distribution of a substrate and interference caused by a film. Another aspect of the present invention provides a surface shape measuring apparatus configured to measure a surface shape of a film formed on a substrate. Surface Shape Measurement-9- 200947142 The apparatus includes an illumination system configured to split broadband light from the light source into measurement light and reference light, the measurement light system illuminates obliquely into the surface of the film, and the reference light system illuminates obliquely Entering a reference mirror; the light receiving system is configured to combine the measured light reflected by the surface of the film and the reference light reflected by the reference mirror with each other, and to direct the combined light to the photoelectric conversion element - and the processing unit The system is configured to calculate the surface shape of the film based on the interference signal detected by the photoelectric conversion member. The incident angle of the measured light on the surface of the film and the incident angle of the reference light to the reference mirror are larger than Brewster (q

Brewster) Corner. The s-polarized light and the P-polarized light included in the measurement light entering the surface of the substrate have the same strength for the photoelectric conversion element. With the surface shape measuring device oriented according to one aspect of the present invention, based on the property of changing the phase of the P-polarized light when the incident angle is larger than the Brewster angle, by suppressing reflection by the rear surface from the photoresist (film) The effects of light can reduce errors in optical measurements. Therefore, the surface shape measuring device can accurately measure the position of the front surface of the film such as the photoresist. In addition, an exposure apparatus is provided which achieves high focus ◎ accuracy with respect to a small depth of focus, and which increases the yield. Further features of the present invention will become apparent from the following description of the exemplary embodiments. [Embodiment] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. It is to be noted that the same components are denoted by the same reference numerals throughout the drawings and the repeated description is omitted. -10-200947142 Fig. 1 is a block diagram of a surface shape measuring apparatus 200 according to a first exemplary embodiment of the present invention. The surface shape measuring apparatus 200 is configured to detect a film on the substrate 3 in the height direction (Z direction), i.e., a device that measures the surface position of the film on its surface. More specifically, the 'surface shape-like measuring apparatus 200' includes a light source 1, a beam splitter (BS) 2a, each of which emits broadband light such as a halogen lamp or an LED (including a so-called white light LED), which is configured to branch light ' And the surface chuck CK is configured to hold the φ target 3 in a holding amount. In addition, the surface measuring apparatus 200 includes a Z gantry 5, a Y gantry 6, and an X gantry 7, which are configured to align the position of the measurement target, the reference mirror 4, the beam splitter (BS) 2b, and are configured to The light reflected by the reference mirror 4 and the light reflected by the substrate 3 are combined with each other, and an image pickup device 8, such as a CCD or CMOS sensor. In this exemplary embodiment, a photoresist is formed on the surface of the substrate 3 as a film. The functions and examples of the various components will be explained below. In Fig. 1, the light emitted by the light source 1 is split into two beams by a beam splitter 2a, each of which has a light amount which is substantially one-half of the emitted light. The two beams enter the substrate 3 and the reference mirror 4 at the same incident angle 0, respectively. The wavelength band of the light source 1 can be set to include wavelengths from 400 nm to 800 nm. However, the wavelength band is not limited to this range and the set wavelength band is not lower than 1 〇〇 nm. When a photoresist is formed on the substrate 3, the substrate 3 should not be irradiated with light having a wavelength of not more than ultraviolet light (3 50 nm) in order to prevent photoresist sensitization. A thick film such as a metal film or a dielectric multilayer film is used as a split film, or a film formed by a film having a thickness of about 1/zm to 5^111 (by SiC or -11 - 200947142)

The beam splitter 'beam splitter 2a' can be formed as a vertical beam splitter. The light metering and reference light are split by the beam splitter 2a, and the measuring light irradiates the substrate 3 and is reflected by the substrate 3 to enter the beam splitter 2b. On the other hand, the reference light system illuminates the reference mirror 4 and enters the beam splitter 2b after being reflected by the reference mirror 4. The reference mirror 4 can be formed by a glass plane mirror having a surface accuracy of about 1 〇 nm to 20 nm. The light reflected by the substrate 3 and the reference light reflected by the reference mirror 4 are combined with each other via the beam splitter 2b, and received by the image pickup device 8. The interference light generated by superimposing the light reflected by the substrate 3 and the reference light reflected by the reference mirror 4 enters the light receiving surface of the image pickup device 8. The beam splitter 2b can be identical to the beam splitter 2a. In the first exemplary embodiment, the incident angles of the substrate 3 and the reference mirror 4, the physical properties of the reference mirror 4, and the optical polarization state are suppressed. An important factor in the effect of reflected light on the back surface of the film on the substrate. These factors will be explained below. First, in this first exemplary embodiment, the reference light and the measurement light are incident on the front surface of the film on the reference mirror 4 and the substrate 3 at an incident angle greater than the Brewster angle (also referred to as the polarization angle). The phase of the p-polarized component of the reflected light is inverted. This feature is explained with reference to FIG. 2. Fig. 2 is a view for explaining the change in the reflectance of each of the s-polarized light and the p-polarized light with respect to the incident angle in the structure of Fig. 3. Here, the reflectance of the photoresist (indicating that the light is 550 nm) is 1 > As seen in Fig. 2, the magnitude of the reflectance of the S-polarized light is negative with respect to the complete change of the incident angle 0 of the photoresist 200947142. On the other hand, the reflectance of the p-polarized light becomes 〇 at an incident angle Θ of about 57 degrees, and the positive and negative signs become positive and negative at a larger incident angle. The incident angle when the reflectance of the p-polarized light becomes 0 is called the Brewster angle or the polarization angle. Therefore, when the incident angle is larger than the Brewster angle, the reflectance of both the s-polarized light and the ^P-polarized light is negative and the two are in phase. Figure 4 illustrates the structure of a high reflectivity substrate composed of, for example, A1 or Cu. The term "high reflectivity substrate" means not only the substrate itself has a high reflectance, but also a substrate in which a film formed on a Si substrate has a high reflectance. 5A and 5B are views for explaining changes in the phase of s-polarized light and p-polarized light included in the reflected light when the high-reflectivity substrate has the structure of Fig. 4. As can be seen from FIG. 5A, when the incident angle θ of the front surface of the photoresist is larger than the Brewster angle, the phase of the p-polarized component in the reflected light from the front surface of the photoresist is inverted 'and the s-polarized light and the p-polarized The light is in phase. On the other hand, according to Snell's law, since the angle of refraction 0' in the photoresist is smaller than the incident angle of the front surface of the photoresist, the incident angle on the substrate becomes smaller than the Brewster angle. Therefore, as seen in FIG. 5B, a phase difference of about π is generated between the s-polarized light component and the p-polarized light component included in the light reflected from the rear surface of the photoresist (ie, the photoresist/substrate interface). . As illustrated in Fig. 5A, the light system enters the reference mirror 4 at an incident angle greater than the Brewster angle such that the s-polarized light component and the p-polarized light component included in the reflected light are in phase. In addition, considering the contrast of the interference signals, the substrate of the reference mirror 4 and the film formed on the substrate are formed of a specific material. For example, a film such as SiO 2 , SiN or SiC may be constituted by a material -13 - 200947142 having a refractive index close to that of the photoresist on the substrate 3. Since the coherence for white light interference is only a few micrometers in length, the reference mirror 4 is composed of a substrate having a thickness of not less than several micrometers to prevent interference caused by reflected light from the surface behind the reference mirror. Alternatively, a film having a refractive index close to the refractive index of the target substrate can be formed on the substrate of the reference mirror 4 to have a thickness of several micrometers or more. Figure 6 illustrates the simulated waveform of the interfering signal measured when incident light enters the substrate of the structure of Figure 4 at an angle of incidence of 80 degrees. In the simulation, the film thickness of the photoresist is set to 2; zm, so that the interference signal formed by the reflected light from the front surface of the photoresist and the interference signal formed by the reflected light from the rear surface of the photoresist are separated from each other. Since the reflected light from the front surface of the photoresist and the reflected light from the rear surface of the photoresist are in phase, there is no phase shift between the s-polarized light component and the p-polarized light component of the interference signal formed by the reflected light from the front surface of the photoresist. . On the other hand, since the interference signal formed by the reflected light from the back surface of the photoresist contains a phase difference π between the reflected light from the back surface of the photoresist and the reflected light from the reference mirror, the s-polarized light component is The phases of the waveforms of the interference signals of the p-polarized light components are opposite to each other. Therefore, by performing the adjustment, the measurement light and the reference light comprise s-polarized light and ρ-polarized light of the same intensity, and the s-polarized light component and the ρ-polarized light-component of the reflected light from the rear surface of the photoresist are mutually Destruction. Therefore, the signal intensity of the reflected light from the rear surface of the photoresist can be reduced. Therefore, by satisfying three conditions, that is, the incident angle 0 is larger than the Brewster angle, the reference mirror 4 uses a material whose refractive index is close to the refractive index of the resist, and the non-polarization, the position of the surface of the substrate can be accurately measured. -14- 200947142 Generally, the light from the light source is polarized. In the interferometer, 'S-polarized light and P-polarized light included in the light from the light source have the same intensity'. The beam splitter has different reflectance and transmittance for polarized light. This makes it difficult to polarize the s in the interference signal formed by the reflected light from the rear surface of the photoresist. The light and the P-polarized light completely match each other. In other words, for example, when light of a non-polarization state is introduced, S-polarized light and P-polarized light in the interference signal formed by the reflected light from the rear surface of the photoresist do not completely cancel each other, and Φ In some cases, it is impeded to accurately measure the position of the front surface of the photoresist. A method of adjusting a photopolarization state according to a first exemplary embodiment of the present invention will be described below. A substrate having a film having a thickness of several micrometers, which is the same as a film on a target substrate, is prepared. In the case of photoresist, or has a refractive index equal to the refractive index of the film. The prepared substrate is placed in a measuring device to adjust the intensity ratio of the S-polarized light to the P-polarized light to minimize the influence of the interference signal formed by the reflected light from the back surface of the photoresist. The substrate used to adjust the intensity ratio of S-polarized light to P-polarized light is constructed using materials that are used in actual semiconductor processes. Specifically, Si, A, and Cu are currently used materials. In an exemplary embodiment of the present invention, the advantages of the present invention are obtained by using an S i substrate or the like to carry out the adjustment, when the target substrate is composed of the materials used in the current semiconductor process. If a substrate material other than Si is used in a semiconductor process in the future, the present invention can be carried out by performing adjustments, although the substrate is made of different materials. However, when the substrate is composed of a material different from Si, the state of the intensity ratio of the adjusted s-polarized light to p-polarized light may vary. In this case, the step of adjusting the intensity ratio can be performed by configuring two or more polarization adjusting elements that can be selectively changed by -15-200947142 and inserting one of the polarization adjusting elements according to the substrate used. Although not illustrated in Fig. 1, between the light source 1 and the beam splitter 2a, a colorless λ/2 plate is provided as a unit for adjusting the polarization state of the light emitted from the light source 1. Combining two crystal materials having different retardation patterns and air between them to form a λ/2 plate, and for providing between two orthogonally polarized light components in the wavelength range of the light source 1 The phase difference of λ/2. The colorless q λ/2 plate can be one of commercially available plates. In addition, a rotary driving unit (not shown) is attached to the colorless λ/2 plate such that the s-polarized light in the interference signal formed by the reflected light from the rear surface of the photoresist is adjusted by rotating the colorless λ/2 plate. The intensity ratio of polarized light. With this adjustment method, the interference signal formed by the reflected light from the front surface of the photoresist and the light reflected from the rear surface of the photoresist can be made in the oblique incident white light interferometer by using the substrate with the thick photoresist structure. The resulting interference signals are separated from each other. In addition to providing a substrate, the polarization state of the light can also be adjusted by preparing a structure having a film on which a film having a thickness of several micrometers is formed on a reference mark 39 (see FIG. 13) provided on the wafer stage. The rate is close to measuring the inverse rate of the film on the target substrate, and adjusting the polarization state of the light using the reference mark having this structure. Therefore, by adjusting the intensity ratio of the interference signals formed by the respective reflected light from the rear surface of the photoresist, the influence of the interference signal formed by the reflected light from the rear surface of the photoresist can be suppressed. When the surface shape of the film is equivalently measured, the film surface exhibits a high reflectance at a large incident angle. Therefore, the incident angle is set to be as large as possible. In the example, the incident angle was set to be 70 degrees or more. -16- 200947142 However, when the incident angle is close to 90 degrees, the difficulty of assembling the optical system occurs 〇 The method of obtaining the interference signal will be described below. In Fig. 1, the substrate 3 is held by a substrate chuck, and the substrate 3 is placed on the Z stand 5, the Y stand 6 and the X stand 7. Driving the Z gantry 5 to obtain an interference signal by the image pickup device 8, as illustrated in FIG. 7, and taking the pixels of the device 8 when storing an image corresponding to the reflection point on the substrate 3 in a memory (not shown) @光强度. When the measurement area on the substrate 3 is changed, the above measurement is performed after the light receiving area of the image pickup unit 8 is pre-aligned by positioning the X stage 7 or the Y stage 6 by operating the X stage 7 or the Y stage 6. In order to accurately control the positions of the X, Y, and Z stands, a laser interferometer is provided for each of the five axes, namely, the X, Y, and Z axes, and the two tilt axes ωχ and c〇y. By performing closed loop control based on the output of the laser interferometer, a more accurate shape measurement can be performed. When the overall shape measurement of the entire substrate 3 is performed by dividing the substrate 3 into a plurality of regions, a more accurate shape data organization can be realized by using a laser interference detector. A method of measuring the shape of the substrate 3 by processing the interference signal that has been obtained by the image pickup device 8 and stored in the memory will now be described. Fig. 7. Describes the interference signal obtained by the image pickup device 8 at a specific pixel. The illustrated interference signal is also referred to as an interferogram. In the graph of Figure 7, the horizontal axis represents the 値 (Z gantry position) measured by the Z-axis interferometer (or another gauge sensor such as a capacitive sensor), and the vertical axis represents image pickup. The output of device 8. The height of the measurement 値 provided at the relevant pixel is determined by the Z-axis interferometer by calculating the position of the peak 値 of the interference signal corresponding to the position of the signal peak -17-200947142. The three-dimensional shape of the substrate 3 can be determined by measuring the height of each of all the pixels of the image pickup device 8. Based on the information obtained from the peak position of the signal and the number of points around the former, the position of the peak can be calculated using a curve approximation (for example, using a quadratic function of the curve). Using the curve approximation, the peak position can be calculated with a sampling interval Zp of 1 / 1 〇 or less along the Z axis, that is, the horizontal axis of Fig. 7. The Z-mount 5 can be actually driven by the step method at a constant pitch Zp, or by the Z-frame 5 being driven at a constant speed and considering the interference signal sampled at a timing at which the sampling pitch Zp is supplied. A conventional FDZ method (described in U.S. Patent No. 5,3,98,113) can also be used as a method of measuring the position of the peak. According to the FDA law, the relative peak position is determined by using the phase slope of the Fourier spectrum. In the white light interference method, the key factor affecting the resolution is the accuracy determined by the position (where the optical path difference between the reference light and the measured light is 〇). To this end, in addition to the FDA method, several edge analysis methods are proposed as conventional techniques, including obtaining the envelope of the white light interference edge by the phase shift method or the Fourier transform method and determining that the light path difference is zero from the maximum edge contrast position. Method, as well as phase crossing method. A second exemplary embodiment of the present invention will be described below along with a surface shape measuring apparatus having a structure different from that of the first exemplary embodiment. Figure 8 is a block diagram of a surface shape measuring apparatus 200 in accordance with a second exemplary embodiment of the present invention. The surface shape measuring device 200 is configured to detect the substrate 3, i.e., the device that measures the Z-direction of the surface of the target. More specifically, the surface shape measuring apparatus 200 includes a light source 1, a first polarizer 9a, a beam splitter 2a configured to split light through 200947142, and a substrate chuck configured to hold the measurement target 3, and The configuration is to align the z-mount 5, Y-frame and X-frame 7 of the target position. The surface shape measuring apparatus further includes a reference mirror 4, a beam splitter 2b, a second polarizer 9b- configured to superimpose light reflected by the reference mirror 4 and light reflected by the substrate 3, and Image pickup device 8, such as a CCD or CMOS sensor. The substrate 3 is a wafer on which a photoresist film is formed. @ The following describes the functions and examples of the various components. In Fig. 8, the light emitted by the light source 1 passes through the first polarizer 9a before entering the substrate 3 and the reference mirror 4. The two beams split by the beam splitter 2a enter the substrate 3 and the reference mirror 4 at the same incident angle Θ, respectively. The light reflected by the substrate 3 and the reference light reflected by the reference mirror 4 enter the beam splitter 2b. Since the light source 1, the incident angle Θ, the beam splitters 2a and 2b, and the reference mirror 4 are the same as those of the first exemplary embodiment, the description of the components will not be repeated here. The beam splitter 2b can be identical to the beam Q splitter 2a. The measurement light and the reference light are received by the device 8 after being passed through the second polarizer 9b. After being irradiated by the substrate 3 and the reference mirror 4, respectively, the measurement light and the reference light are superimposed on each other via the beam splitter 2b to generate interference light entering the light receiving surface of the image pickup device 8. The method of obtaining an interference signal using light from a light source and the method of processing the interference signal are the same as those of the first exemplary embodiment. Therefore, the method will not be repeated here. The difference between the second exemplary embodiment and the first exemplary embodiment is that the polarizers 9a and 9b are disposed upstream and downstream of the optical path -19-200947142 of the substrate 3 and the reference mirror 4, respectively. With this configuration 'after the polarization state of the light emitted from the light source 1 has been changed to linear polarization', the light enters the substrate 3 and the reference mirror 4 at an incident angle greater than the Brewster angle. The light reflected by the substrate 3 and the reference mirror 4 is received by the image pickup device 8 in the same linear polarization state as the polarized light incident on the substrate 3 and the reference mirror 4. Referring to Fig. 9, the change of the polarization state of the light emitted by the light source until it is received by the image pickup device 8 in the second exemplary embodiment will be described below. The polarization state of the light emitted by the light source 1 is changed by the first polarizer 9a. Fig. 9 illustrates the case where the polarization state of the light which has been emitted by the light source 1 and passed through the first polarizer 9a is linearly polarized in the +45° direction. The phase of the light reflected by the substrate 3 and the reference mirror 4 changes in relation to the angle of incidence illustrated in Figures 2, 5A and 5B. Therefore, the direction of polarization of the light reflected from the front surface of the film is not changed, and the reflected light maintains a linear polarization of +45°. On the other hand, since the phase difference π is generated between the light reflected by the film/substrate interface and the light reflected by the reference mirror 4, the light reflected by the film/substrate interface is changed to linear polarization in the -45° direction. . Therefore, the interference signal formed by the light reflected from the front surface of the film and the film/substrate interface has two orthogonal (+45° direction and -45° direction) linear polarization components. Therefore, after being reflected by the substrate 3 and the reference mirror 4, only the component of the linear polarization in the +45° direction can be extracted through the second polarizer 9b, and the light reflected by the film/substrate interface can be excluded. The component of the interference signal. Similarly, when the polarization state of the light that has been emitted by the light source 1 and passed through the first polarizer 9a is linearly polarized in the -45 direction, the light reflected by the film/substrate interface is referenced by the reference mirror 4 A phase difference π is generated between the reflected light, and only the component of the interference signal formed by the light emitted by the inverse -20-200947142 of the front surface of the film can be excluded. In other words, by using the above reference mirror 4, setting the incident angle 0 to be greater than the Brewster angle, and illuminating the incident light of the linearly polarized polarization state, the interference formed by the light reflected by the film/substrate interface can be suppressed. The effect of the signal. Although it is necessary to use a polarizer for a large amount of light compared to the first exemplary embodiment, the interference signal formed by the light reflected by the photoresist-back surface can be effectively removed, and the coating can be accurately measured. The surface shape of the photoresist on the wafer. φ Hereinafter, a method of adjusting the polarization state of light in the second exemplary embodiment will be described. A substrate having a film having a thickness of several micrometers is prepared, the film being the same as the film on the measurement target substrate (in this case, the photoresist) or having the same refractive index as the refractive index of the film. The prepared substrate is placed in the measuring device, and the intensity ratio of the s-polarized light to the P-polarized light is adjusted to minimize the influence of the interference signal formed by the reflected light from the back surface of the photoresist. Attaching a rotary driving unit (not shown) to each of the polarizers 9a and 9b in FIG. 8 enables the interference signal formed by the reflected light from the rear surface of the photoresist to be adjusted by the rotary polarizers 9a and 9b Intensity ratio in . With this adjustment method, due to the use of a substrate having a thick photoresist structure, the interference signal formed by the reflected light from the front surface of the photoresist and the reflected light from the rear surface of the photoresist can be formed in the oblique incident white light interferometer. The interference signals are separated from each other. In addition to providing a substrate, the photopolarization state can also be adjusted by preparing a structure having a film in which a film having a thickness of several micrometers is formed on a reference mark 39 (see FIG. 13) provided on the wafer stage, and the reflectance thereof is obtained. The inverse ratio of the film on the target substrate is measured, and the photopolarization state is adjusted using the reference mark having this structure. Therefore, by adjusting the intensity ratio of the interference signals formed by the above -21 - 200947142 reflected light from the rear surface of the photoresist, the influence of the interference signal formed by the reflected light from the rear surface of the photoresist can be suppressed. In addition to the rotary polarizer, the polar state of the light from the light source can also be adjusted by arranging the λ/2 plate, including the rotary drive unit downstream of the polarizer and the rotating λ/2 plate. When measuring the position of the front surface of the photoresist, the interference signal formed by the light reflected from the front surface of the photoresist provides a signal (S) to be measured, and the interference signal formed by the light reflected by the surface of the photoresist becomes Noise (Ν).于 At a higher S/N ratio, a higher-precision shape measurement of the front surface of the photoresist can be performed, and the intensity ratio described above can be adjusted according to the accuracy required for the shape measurement. For example, adjusting the intensity ratio will make the S/N ratio not less than 1 〇. When more accurate measurements are required, the S/N ratio can be set to be no less than 20 or 30. As a result, in this second exemplary embodiment, the linearly polarized light that has passed through the polarizer 9a is adjusted to fall within ±1° with respect to the +4 5° direction and the -45° direction. The reason for this is that when the linearly polarized light is oriented at an angle different from: L45, the interference signals formed by the light reflected from the front surface of the film and the film/substrate interface are not orthogonal to each other. Therefore, the S/N ratio is lowered due to the interference of the component present and the light reflected by the rear surface of the photoresist, and the difficulty in performing highly accurate surface shape measurement is caused. For example, setting the frequency of adjusting the polarization state causes the delivery device to perform an adjustment, and the adjustment is performed only when the device component, such as a light source, is replaced. In addition, it is also possible to separately measure the target substrate to prepare a relatively thick (several micrometer) film and to measure the polarization state by using a substrate on which a relatively thick film is formed to adjust the polarization state. The film surface shape of the substrate. -22- 200947142 Even if the second polarizer 9b is not provided, the reflected light from the front surface of the photoresist and the rear surface of the photoresist is received as two linear polarization components. In this case, when the received light is two orthogonal linear polarization components, the image of the interference signal formed by the light reflected by the rear surface of the photoresist can be suppressed, because the interference is only in phase. The reference light and the light reflected by the back surface of the photoresist are generated. From the standpoint of the contrast of the interference signals, the received light is the desired of two orthogonal linear polarization components. However, in practice, the phase changes due to the influence of the beam splitter 0 and the like, and the light that is not easily received is completely linearly polarized. For this reason, the second polarizer 9b is used in the second exemplary embodiment to further suppress the influence of the reflected light from the rear surface of the photoresist. When the shape measurement of the complex measurement region is performed on the substrate 3, After the wafer stage has been removed to align each predetermined area, an interference signal and an interference signal are processed similarly to the first exemplary embodiment by driving the X stage and the Y stage. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS A third exemplary embodiment of the present invention will be described below along with a surface shape measuring apparatus having a structure different from that of the first and second exemplary embodiments. Figure 10 is a block diagram of a surface shape measuring apparatus 200 in accordance with a third exemplary embodiment of the present invention. The surface shape measuring device 200 is configured to detect the substrate 3, i.e., the device that measures the Z-direction of the surface of the target. More specifically, the surface shape measuring device 200 includes a light source 1, a first polarizer 9a, a first wavelength plate 10a, a beam splitter 2a configured to split light, and configured to hold a measurement target The substrate chuck CK of 3, and the Z gantry 5, the Y gantry, and the X gantry 7 configured to align the target position. -23- 200947142 The surface shape measuring device further comprises a reference mirror 4, a beam splitter 2b, a second polarizer 9b configured to combine the light reflected by the reference mirror 4 and the light reflected by the substrate 3 with each other The second wavelength plate 10b, and the image pickup device 8, such as a CCD or CMOS sensor. The functions and examples of the various components will be described below. - In Fig. 10, the light emitted by the light source 1 passes through the first polarizer 9a and the first wave plate 10a before entering the substrate 3 and the reference mirror 4. The two beams split by the beam splitter 2a are respectively injected at the same angle of incidence &

The substrate 3 and the reference mirror 4 are inserted. The light reflected by the substrate 3 and the reference light reflected by the reference mirror 4 enter the beam splitter 2b. Since the light source 1, the incident angle Θ, the beam splitters 2a and 2b, and the reference mirror 4 are the same as those of the first exemplary embodiment, the description of the components will not be repeated here. The beam splitter 2b can be identical to the beam splitter 2a. The measurement light and the reference light are received by the image pickup device 8 after passing through the second wave plate 10b and the second polarizer 9b. After being reflected by the substrate 3 and the reference mirror 4, respectively, the measurement light and the reference light are superimposed on each other on the light receiving surface of the image pickup device 8 to generate Q light interference. A wavelength plate is formed from a colorless λ/4 plate. Two crystal materials having different retardation characteristics and air interposed therebetween are combined to form a colorless λ /4 plate, and it is used to provide a Λ /4 phase difference between two orthogonally polarized light components in a wide frequency band. A commercially available board can be provided as a colorless λ /4 board. The method of using the interference signal obtained from the light source and the method of processing the interference signal are the same as those in the first exemplary embodiment. Therefore, those methods will not be repeated here. -24- 200947142 The difference between the third exemplary embodiment and the first embodiment is that a set of polarizers 9a and a wave plate 10a and a group of elements are disposed in the optical paths upstream and downstream of the substrate 3 and the reference mirror 4, respectively. The device 9b and the wavelength plate l〇b. With this configuration, after the polarization state of the light emitted by the light source is changed from linear polarization (such as P 'polarized light) to circular polarization, light is caused to enter at the incident angle 0 - the substrate 3 and the reference mirror 4 each. The reflected light from the substrate 3 and the reference mirror 4 is received by the image pickup Q device 8 only by the light component oscillating in the same direction as the linear polarization described above. The change of the photopolarization state in this third exemplary embodiment will be described below with reference to Fig. 11. The polarization state of the light emitted from the light source 1 is changed to linear polarization by the polarizer 9a, and then becomes circularly polarized by the wavelength plate 10a. The diagram illustrates the polarization state of light that has been emitted by the light source 1 and that has passed through the polarizer 9a and the wavelength plate 10a as a right-handed circular polarization. When the reference mirror 4 is used, the phase of the reflected light from the substrate 3 and the reference mirror 4 changes in relation to the incident angle as shown in Figs. 2, 5A and 5B. Therefore, the direction of rotational polarization of the reflected light from the front surface of the film does not change, and the reflected light maintains the right hand circular polarization. On the other hand, since a phase difference π is generated between the reflected light from the film/.substrate interface and the reflected light from the reference mirror 4, the reflected light from the film/substrate interface becomes left-handed circular polarization. . Therefore, after the circularly polarized light is changed to linearly polarized light via the wavelength plate 10b, the right-handed and left-handed circular polarization states formed from the reflected light from the front surface of the film and the film/substrate interface can be formed. The interference signals are converted into P polarization components and s polarization components, respectively. Therefore, the component of the interference signal -25-200947142 formed by the reflected light from the front surface of the film can be removed by simply extracting the p-polarized component by the polarization 9b. In other words, by using the above-described reference mirror 4, the incident light is irradiated at an incident angle 0 larger than the Brewster angle in the circular polarization state, the circular polarization is converted into a linear polarization component via the wavelength plate, and the polarization is obtained. The device extracts the component of the reflected light from the front surface of the photoresist, and suppresses the influence of the interference signal formed by the reflected light from the back surface of the photoresist. Although a larger amount of light is required in the first exemplary embodiment due to the use of the polarizer and the wavelength plate,

The interference signal formed by the reflected light from the rear surface of the photoresist is effectively removed, and the surface shape of the photoresist coated on the wafer can be accurately measured. If the adjustment method can be implemented as described above with reference to Q FIG. 6, the front surface signal (ie, the interference signal formed by the reflected light from the front surface of the photoresist) and the back surface signal are formed due to the formation of a sufficiently thick film on the substrate. The interference signals formed by the reflected light from the rear surface of the photoresist are separated from each other, and the relative angles of the polarizers 9a and 9b with the wave plates 10a and 10b are adjusted such that the relative intensity of the back surface signal with respect to the front surface signal is minimized. Even if the second polarizer 9b is not provided in the third exemplary embodiment, the reflected light from the front surface and the rear surface of the photoresist is received as a polar component of the two orthogonal lines, and only by the same phase. The reference light and the light reflected by the front surface of the light group interfere. Therefore, the influence of the interference signal formed by the opposite light of the surface of the photoresist can be suppressed. However, actually, the phase change is moved due to the influence of the beam interferer or the like, and it is difficult to obtain the received light in a completely linearly polarized state. For this reason, the second polarizer 9b is used in the third exemplary embodiment to further suppress the interference signal of the reflected light from the rear surface of the photoresist. The adjustment of the polarization state can be carried out by attaching the rotary drive unit to the polarizers 9a and 9b or the wavelength plates -26-200947142 10a and 1 Ob in a manner similar to the above-described exemplary embodiment. More specifically, a substrate having a film having a thickness of several micrometers is prepared, the film being the same as the film on the measurement target substrate (in this case, the photoresist) or having the same refractive index as that of the film. The prepared substrate is placed in a measuring device. ' Next, the intensity ratio of the s-polarized light to the p-polarized light is adjusted such that the interference signal formed by the reflected light from the rear surface of the photoresist is made by the polar-polarizers 9a and 9b or the wavelength plates 10a and 10b. The impact is minimized. 0 When the shape measurement is performed on the complex measurement area on the substrate 3, after the wafer stage has been moved to be aligned with each predetermined area by driving the X stage and the Y stage, similar to the first exemplary embodiment Obtaining and Processing Interference Signals Three exemplary embodiments have been described above, and for ease of illustration, the exemplary embodiments do not use lenses or the like. Figure 12 is a block diagram of another surface shape measuring apparatus 200 in accordance with the present invention. An exemplary embodiment of an optical system constructed using a lens or the like will be described below with reference to Fig. 12 . The light emitted from the light source 1 is collected by the condensing lens 11 and passed through the transmission slit plate 30. Through the optical system 16 including the lens 12, the lens 42 and the aperture stop 22, after the two beams are split by the beam splitter 2a, the collected light is imaged on the respective surfaces of the substrate 3 and the reference mirror 4. The reflected light from the substrate 3 and the reference mirror 4 is superimposed on each other via the beam splitter 2b and imaged on the image pickup device 8 via the image optical system 24 including the lens 52, the lens 62, and the aperture stop 13. Therefore, the surface of the substrate 3 can be imaged on the image pickup device 8. A transmission slit plate 30 is used to define the measurement area. -27- 200947142 Although the three exemplary embodiments described above are in the case where the incident angles of the substrate 3 and the reference mirror 4 are the same, as long as the reference mirror 4 satisfies the above conditions, the incident angles of the substrate 3 and the reference mirror 4 No need to be the same. Further, in order to increase the contrast of the interference signals, the individual intensity of the interference pattern formed by the reflected light from the substrate 3 and the reference mirror 4 can be changed by adjusting the incident angles of the substrate 3 and the reference mirror 4. Figure 13 is a block diagram of a semiconductor exposure apparatus according to a fourth exemplary embodiment of the present invention, including a surface shape measuring apparatus. As illustrated in FIG. 13, the exposure apparatus includes an illumination apparatus 800, a mask stage RS on which the mask 31 is placed, a projection optical system 32, a wafer stage WS on which the wafer 3 is placed, and a configuration A reference plate (mask) 39 on the wafer table WS. Further, the exposure apparatus includes a surface position measuring device 33, a processing unit 400 relating to the measuring device 33, a surface shape measuring device 200, and a processing unit 410 related to the measuring device 200. The surface shape measuring device 200 may be one of the devices according to the first to third exemplary embodiments. In the fourth exemplary embodiment, in order to more clearly show their functions, the surface position measuring device 33 and the surface shape measuring device 200 are referred to as a focus measuring device 33 and a focus calibration device 200, respectively. The control unit electrically connected to the illumination device 800 includes a CPU and a body, a mask table RS, a wafer table WS, a focus measuring device 33, and a focus calibration device 200 for controlling the operation of the exposure device. In the fourth exemplary embodiment, when the focus measuring device 3 3 detects the surface position of the wafer 3, the control unit 1 100 further performs calculation and control to correct the measured 値. The illuminating device 800 illuminates the light 200947142 cover 31 on which the circuit pattern to be transferred is formed. The illumination device 800 includes a light source unit 800 and an illumination optical system 801. The illuminating optical system 801 has a function of uniformly illuminating the reticle 31 and an illuminating function of polarization. The light source unit 800 is for example a shot. The laser can be an ArF excimer laser having a wavelength of about 1 93 • nm or a KrF excimer laser having a wavelength of about 248 nm. The type of light source is not limited to excimer lasers. More specifically, an F2 laser having a wavelength of about 157 nm or an EUV (ultraviolet light) having a wavelength of about 20 nm or less can also be used. Illumination optics 800 is an optical system configured to illuminate an illuminating optical surface by using a beam of light emitted by source unit 800. In the fourth exemplary embodiment, the light beam is shaped via an exposure slit having a predetermined optimum shape for exposure, and the shaped beam system is irradiated to the reticle 31. This illumination optical system 801 includes a lens, a collecting lens, a fly's eye lens, an aperture stop, a collecting lens, a slit, and an imaging optical system which are sequentially disposed in the illumination optical system 801.光 For example, the reticle 31 is made of quartz, and the circuit pattern to be transferred is formed on the reticle 31. The reticle 31 is supported and driven by the reticle stage RS. The diffracted light from the light cover 31 passes through the projection optical system 32 and is projected onto the wafer 3. The reticle 31 and the wafer 3 are arranged to be optically conjugated. The circuit pattern on the mask 31 is transferred onto the wafer 3 by scanning the mask 31 and the wafer 3 at a speed ratio corresponding to the desired reduction factor. The exposure apparatus includes a mask detection unit (not shown) based on a light oblique incidence system. The reticle 31 is located at a predetermined position, and the position of the reticle 31 is detected by the reticle detecting unit. -29- 200947142 The mask table RS supports the reticle 31 via a reticle holder (not shown) and is connected to a moving mechanism (not shown). The moving mechanism is composed of a linear motor, and drives the mask table RS in the X-axis direction, the γ-axis direction, the z-axis direction, and the direction in which the respective axes rotate, thereby moving the mask 31. The projection optical system 32 has a function of imaging a light beam from a target plane onto an image plane. In the fourth exemplary embodiment, the circuit pattern formed by the projection optical system 32 from the photomask 31 will be on the wafer 3 on which the light is imaged. Projection optics 32 can be, for example, an optical system including a plurality of lens elements, an optical system (a catadioptric system) including a plurality of lens elements and at least one concave lens, or a plurality of lens elements and at least one diffractive optical element such as a phase hologram Optical system. Wafer 3 is a processing target and is photoresist coated onto the substrate. In the fourth exemplary embodiment, the wafer 3 is also a detection target, and the surface position is detected by the focus measuring device 33 and the focus calibration device 200. In another exemplary embodiment, the wafer 3 is one of a liquid crystal substrate or other processing target. The wafer table WS supports the wafer 3 via a wafer chuck (not shown). Together with the mask stage RS, the wafer table WS moves the wafer 3 by the linear motor in the X-axis direction, the γ-axis direction, the Z-axis direction, and the direction in which the respective axes rotate. Further, the position of the mask table rs and the position of the wafer table WS are monitored by, for example, a 6-axis laser interferometer 81, and the two stages are driven at a constant speed ratio. The point at which the measurement surface position of the wafer 3 is measured (i.e., the focus) will be described below. In the fourth exemplary embodiment, the wafer surface shape is measured by the focus measuring device 3 3 while scanning the wafer table ws on the entire area of the wafer 3 of the -30-200947142 in the scanning direction (Y direction). . Further, the wafer table ws is stepped AX in the direction perpendicular to the scanning direction (X direction). Next, shape measurement is performed on the entire surface of the wafer 3 by repeatedly measuring the position of the wafer surface in the scanning direction. To increase the output 'by using the complex focus measuring device' 33, the different surface positions of the wafer 3 can be measured at the same time. The focus measuring device 3 3 uses an optical height measuring system. In other words, the focus measuring device 33 uses a large angle of incidence to direct light to the wafer and a method of detecting the movement of the image reflected by the surface of the wafer by a @ position detector such as a CCD sensor. In particular, the beam is directed to a plurality of points to be measured on the wafer, and the reflected light from the points is directed to an individual sensor that has calculated the tilt of the exposure target surface based on the height measurement information obtained at the different points. The focus and tilt detection system will be explained below. First, the structure and operation of the focus measuring device 33 will be explained. Referring to FIG. 14, the focus measuring device 3 3 includes a light source 105, a collecting lens 106, a pattern plate 107 having a plurality of rectangular transmission slits arranged adjacent to each other, lenses 108 and 111, a wafer 103, and a wafer round table (WS). 104, mirrors 109 and 110, and photodetector 112, such as a CCD sensor. The symbol 012 indicates that the projection lens is reduced to project a reticle (not shown) onto the wafer 103 for exposure. The light emitted from the light source 105 is focused by the condensing lens 106 and irradiated onto the pattern plate 107. The light having passed through the slit of the pattern plate 107 is irradiated to the wafer 103 via the lens 108 and the mirror 109 at a predetermined angle. The pattern plate 107 and the wafer 103 are in an imaging relationship with respect to the lens 108, and the spatial image of each slit of the pattern plate 107 is formed on the wafer. The reflected light from the wafer 103 is received by the CCD sensor 112 via the mirror 110 and the lens Π1. By the lens 111, the slit image of the crystal -31 - 200947142 circle 103 is re-imaged on the CCD sensor 112' and the slit image signal corresponding to the slit of the pattern plate 107 as indicated by l〇7i is obtained. The position of the wafer 103 in the Z direction is measured by detecting the positional shift of the signals on the CCD sensor 112. Assuming that the incident angle is Θ, when the wafer surface changes dz from the position w1 to w2 in the Z direction, the amount of movement of the wafer 3 on the optical axis can be expressed by the following formula: - ml=2*dz* Tan0 In (1) ❹ For example, assuming an incident angle of 84 degrees, m 1 = 1 9 · dz is obtained. This indicates that the shift amount is 19 times the wafer shift amount. The amount of displacement on the photodetector is obtained by multiplying (1) and the magnification of the optical system (i.e., by the imaging magnification of the lens 111). The exposure method using the above-described exposure apparatus according to the fourth exemplary embodiment of the present invention will be described in detail below. Figure 15 is a flow chart showing the overall steps of the exposure method when the exposure apparatus according to the fourth exemplary embodiment of the present invention is used. First, in step S1, the wafer 3 is loaded into the device. 0 Next, it is determined in step S10 whether or not the focus measurement device 33 performs the focus point calibration. According to, for example, "whether the relevant wafer is the wafer of the header in the batch, "whether the relevant wafer is the wafer of the header in the plurality of batches" and "whether the relevant wafer is in the process of strictly demanding focus accuracy" The information of the wafer is automatically determined. This information is previously stored by the user in the exposure device. If it is determined in step S10 that the focus calibration is not required, the program flow proceeds to step S1 000, where on the wafer. Performing the normal exposure sequence. On the other hand, if it is determined in step S1 that the focus calibration is required, the program flow proceeds to the focus calibration sequence in step-32-200947142 SI 00. In step S100, 'execution illustrated in FIG. 16 is performed. Flowchart. First, the wafer table WS is driven to properly position the reference plate 39 under the focus measuring device 33. The reference plate 39 is formed of a glass plate having a high surface precision, a so-called optical flat. The surface of 39 has a reflectance • a uniform sentence to prevent an area of measurement error caused by the focus measuring device 33. The measurement is performed on the area. The reference plate 39 can also be set as a partial package φ A board of various calibration marks required for other calibrations performed by the exposure apparatus (such as for the alignment detection system and evaluation of the projection optical system). In step S101, the focus measurement device 33 detects the Z of the reference plate 39. The position in the direction 'and the stored amount in the device in step S102. Then 'in step S 1 0 3' drive the wafer table w S to properly position the reference plate 39 under the focus calibration device 200, and by focus The calibration apparatus 200 performs shape measurement at the same position in the X γ plane on the reference plate 39 of the measurement area of the focus measurement device 33. In step S1 0 4, the shape φ measurement data Pm is stored. In the device, the first offset 1 is calculated in step S105. As shown in Fig. 17, the offset is obtained as the focus calibration device. The measurement of the measurement unit Pm and the focus measurement device 3 3 The difference between 値〇m. Offset 1 is a measurement error of the focusless measuring device 3 3 because the measurement system is performed on the optically uniform surface of the reference plate 39. Therefore, in the ideal case, the offset 1 should be zero. However, the offset 1 is due to the system in the scanning direction of the wafer table WS. The shift is generated by the long-term drift of the focus measuring device 33 or the focus calibration device 200. For this reason, the offset 1 measured based on the cycle basis is desired. -33- 200947142 The reference plate 39 is completed by the above steps. The focus calibration sequence S100. After the focus calibration sequence S100, the focus calibration sequence S200 using the wafer 3 is performed. In step S201 of Fig. 16, the wafer table WS is driven so that the measurement position of the focus measuring device 3 3 is appropriate. Positioning the wafer table 3. It is assumed that the (wafer surface) measurement position Wp on the wafer 3 matches the measurement position in the exposure sequence described below. In addition, the wafer is detected by the focus measurement device 33 in step S201. The position in the Z direction at the position Wp is measured, and the measurement amount Ow is stored in the device in step S202. In step S203, the wafer table WS is driven to properly position the wafer 3 under the focus calibration apparatus 200, and the shape measurement at the measurement position Wp on the wafer 3 is performed by the focus calibration apparatus 200. In step S204, the shape measurement data Pw is stored in the device. The measurement locations on wafer 3 can be selected from the following modes, including: one dot per wafer, one spot per shot, all points in one emission, all points in a complex transmission, and all points in a wafer. In step S20 5, the second offset 2 is calculated. As illustrated in FIG. 17, the offset 2 is calculated between the measurement of the focus calibration apparatus 200 and the measurement of the focus measurement device 3 3 for each measurement position Wp on the wafer 3. difference. The difference between offset 2 and offset 1 is calculated for each measurement point on the wafer 3 in step S206. The offset of the measurement point on the wafer 3 can be obtained by the following formula (2): °P(i) = [Ow(i) - Pw(i)] - (Om - Pm) (2) 200947142 Where i represents the number of points representing the measurement position on the wafer 3. Thus, the focus calibration sequence S2000 using the wafer 3 is completed. The exposure sequence S1000 performed after completion of both the focus calibration sequences S100 and S200 will be described below. Figure 18 is a flow chart detailing the exposure sequence - S 1 000. Referring to Fig. 18, the wafer alignment is performed in step S1010. Wafer alignment is performed by detecting the marked locations on the wafer by aligning the fields of view (not shown) and associated exposure equipment to the wafers in the XY plane. In step S1 0 1 1, the surface position of the predetermined position on the wafer 3 is measured by the focus measuring device 3 3 . The predetermined location includes points measured by the calibration sequence using wafer 3. Therefore, the shape of the entire wafer surface is measured by correcting the respective amounts of the offsets Op (i) calculated according to the equation (2). The corrected wafer surface shape data is stored in the exposure apparatus. In step S1012, for the first exposure illumination, the wafer 3 is moved from the position below the focus measuring device 33 to the exposure position below the projection lens 102 by the wafer table WS. At the same time, according to the surface shape data of the wafer 3, the processing unit associated with the exposure apparatus prepares the surface shape information for the first exposure illumination, and calculates the offset from the exposure imaging plane. Then, according to the calculated offset from the exposure imaging plane, the wafer stage is driven in the Z direction and the oblique direction to perform the matching wafer surface shape in the height direction substantially in the exposure slit unit. operating. In step S1013, the exposure and scanning wafer stage WS is performed in the Y direction. After the first exposure irradiation is completed in this manner, it is determined in step S1014 whether or not the exposure is still not performed. If the exposure is still not performed, the process returns to step S1012. Next, as the first exposure illumination, the surface shape data for the next exposure illumination is prepared, and the exposure is performed when the wafer stage is driven in the -35-200947142 Z direction and the oblique direction to perform the exposure in the height direction, substantially exposing The operation of matching the surface shape of the wafer in units of slits. In step S1014, it is determined again whether or not the exposure illumination to be performed (i.e., the exposure has not been performed) is present. Then, the above operation is repeated until no exposure is still performed. After all exposure exposures are completed, in step 81015, the wafer 3 is taken out of the apparatus and the exposure sequence is ended. In the fourth exemplary embodiment, the surface shape data for the relevant exposure illumination and the amount of movement from the exposure imaging plane are prepared to determine the amount to be driven of the wafer table just before each exposure illumination. However, the timing of the individual steps can be corrected before the first exposure, while the surface shape data for all exposures is prepared, and the amount of movement from the exposure imaging plane is calculated to determine the amount of wafer to be driven. In addition, the wafer table WS is not limited to a single station. For example, it may be composed of so-called two stages, that is, an exposure stage used in exposure, and a measuring stage for performing wafer alignment and measuring the shape of the surface. In the latter case, the focus measuring device 3 3 and the focus calibration device 0 200 are mounted on the measuring station. In the fourth exemplary embodiment as described above, a method of adjusting the polarization state of light in the surface shape measuring device (focus calibration device) 200 when the surface measuring device 200 is mounted in the exposure device will be explained. Although the photopolarization state can be adjusted by using a photoresist coated with a thickness of several micrometers as described in the above second exemplary embodiment, the exemplary embodiment described below is based on the exposure light used in the exposure apparatus. Polarization implementation adjustment method. The illumination optical system 810 of the exposure apparatus generally includes a polarization state in which the polarization illumination unit is directed to -36-200947142 to illuminate the light of the reticle. Therefore, when the exposure apparatus is delivered, the polarization state of the light in the surface shape measuring apparatus 200 is adjusted based on the polarization of the exposure light. More specifically, first, linearly polarized light in a predetermined state (e.g., p-polarized light) is formed by using an illuminating unit in the illuminating optical system 80 1 for exposing light. Next, the exposure light in a predetermined linear polarization state is caused to enter vertically into the polarizer including the rotary driving unit. In addition, the polarizer is rotated to determine the position at which the transmittance is the largest or smallest. This results in the use of φ as the exposure light corresponding to the polarization state of the P or S polarized light. Subsequently, the polarizer is mounted such that light from the source in the focus calibration device 200 enters the polarizer vertically. When this adjustment method is applied to the surface shape measuring apparatus according to the second exemplary embodiment illustrated in Fig. 8, the adjustment is completed by rotating the polarizer by 45 degrees using the rotation driving unit. Therefore, the adjustment of the polarization state can be performed by using an exposure apparatus without preparing a special substrate. After the exposure device is delivered, based on the polarization of the exposure light, after the polarization state is adjusted in the surface shape measuring device, the base material having a thick photoresist can be prepared and the rotary driving unit according to the wafer structure to be processed can be used. Fine-tune the polarization state. Because of the wafers, the substrates to be measured and processed by the semiconductor exposure equipment, the complex circuit patterns, scribe lines, etc., the probability of occurrence of reflectance distribution, local tilt, etc., is quite high. Therefore, the present invention is extremely effective in reducing measurement errors caused by reflectance distribution, local tilt, and the like. More accurate wafer surface position measurement improves the precise focus alignment of the optimal exposed surface to the wafer surface, thereby enhancing the performance of the semiconductor device and increasing yield. For example, a step of exposing a substrate coated with a photoresist (such as a wafer or a glass plate - 37 - 200947142), a step of using an exposure apparatus according to one of the above exemplary embodiments, developing a substrate for exposure, and Other steps known in the prior art may be fabricated into devices such as semiconductor integrated circuit devices or liquid crystal display devices. While the invention has been described with reference to the exemplary embodiments, it is understood that the invention is not limited to the disclosed embodiments. The scope of the following patent application is to be construed in a broadest sense as the BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a surface shape measuring apparatus according to a first exemplary embodiment of the present invention. Figure 2 is a graph of the change in the reflectance (i.e., Fresnel relationship) associated with the incident angle. Figure 3 illustrates the model used in the simulation illustrated in Figure 2. Figure 4 illustrates the model used in the simulation illustrated in Figures 5A and 5B. Figure 5A is a diagram illustrating the phase change of light reflected by the front surface of the photoresist (i.e., the air/photoresist interface) with respect to the angle of incidence. Figure 5B is a diagram illustrating the phase change of light reflected by the back surface of the photoresist (i.e., the photoresist/A1 interface) with respect to the angle of incidence. Fig. 6 is a view for explaining interference signals formed by respective lights reflected by the front and rear surfaces of the photoresist. Fig. 7 is a view for explaining an interference signal obtained in the first embodiment of the present invention. -38- 200947142 Fig. 8 is a block diagram of a surface shape measuring apparatus according to a second exemplary embodiment of the present invention. Figure 9 illustrates the polarization states of various points in the surface shape measuring apparatus according to the second exemplary embodiment of the present invention. Figure 10 is a block diagram of a surface shape-measuring apparatus in accordance with a third exemplary embodiment of the present invention. Fig. 11 illustrates the polarization states of various points in the surface shape measuring apparatus according to the third exemplary embodiment of the present invention. Figure 12 is a block diagram of another surface-facing measuring apparatus according to the present invention. Figure 13 is a block diagram of a semiconductor exposure apparatus including a surface shape measuring apparatus according to a fourth exemplary embodiment of the present invention. Figure 14 is a surface position amount used in a fourth exemplary embodiment of the present invention. A block diagram of the test equipment. ® Figure 15 is a flow chart showing the exposure sequence in the fourth exemplary embodiment of the present invention. Figure 16 is a flow chart of a method of correction in a fourth exemplary embodiment of the present invention. Figure 17 is an explanatory view for explaining a correction method in a fourth exemplary embodiment of the present invention. Figure 18 is a flow chart showing an exposure method in a fourth exemplary embodiment of the present invention. Figure 19 is a diagram for explaining the problem of the conventional surface position measuring device -39-200947142. Fig. 20 is a view for explaining an example of a signal file measured by the conventional surface position measuring device of Fig. 9. Fig. 21 is a view for explaining the problem of the conventional surface shape measuring device. Fig. 22 is a view for explaining a problem of the conventional surface shape measuring device. Figure 23 is a block diagram of a conventional surface shape measuring apparatus. _ [Main component symbol description] 1 : Light source 2a : Beam splitter 2b : Beam splitter 3 : Substrate 4 : Reference mirror

5 : Z gantry U 6 : Y gantry 7 : X gantry 8 : Image pickup device 9 a : First polarizer 9 b : Second polarizer 10 a : First wavelength plate 1 〇 b : Second wavelength plate 1 1 : Poly Optical Lens-40- 200947142 12 : Lens 13: Aperture Stop 16: Optical System 22: Aperture Stop - 24: Imaging Optical System. 30: Transmission Slit Plate 3 1: Mask a 32: Projection Optical System 33: Surface Position measuring device 39: reference plate 4 2 : lens 52 : lens 62 : lens 81 : laser interferometer 10 1 : light source 〇 102 '·reduced projection lens 103 : lens 1 04 : wafer table 105 : beam splitter 106 : concentrating lens 107 : pattern plate l 〇 7i : image signal 108 : lens 109 : mirror - 41 200947142 1 1 0 : mirror 111 : lens 1 1 2 : photodetector 130 : reference mirror 1 7 0 : beam combiner 1 7 1 : Lens 173 : Lens 1 7 5 : Photoelectric conversion element 200 : Surface shape measuring device 3 6 0 : Sample 397 : Actuator 400 : Processing unit 410 : Processing unit 8 0 0 : Irradiation device 8 0 1 : Illumination optical system 1 1 0 0 : Control unit -42

Claims (1)

200947142 VII. Patent Application Range: 1 · A surface shape measuring device configured to measure a surface shape of a film formed on a substrate, the device comprising: an illumination system configured to The light-band of the broad band of the light source splits into a metering light and a reference light that is irradiated to obliquely enter a surface of the film that is irradiated to obliquely enter a reference mirror. a system configured to combine the measured light reflected by the surface of the film and the reference light reflected by the reference mirror with each other' and combine the combined light to a photoelectric conversion element; and a process a unit configured to calculate the surface shape of the film according to an interference signal detected by the photoelectric conversion element, wherein an incident angle of the measurement light on the surface of the film and the reference mirror An incident angle of the reference light is greater than a Brewster angle, and the S-polarized light and the P-polarized light included in the measurement light entering the surface of the substrate The photoelectric conversion elements have the same intensity. 2. The surface shape measuring apparatus according to claim 1, further comprising: a polarization adjusting unit configured to adjust s-polarized light included in the broadband light from the light source An intensity ratio between the p-polarized light, wherein the polarization adjustment unit adjusts the intensity ratio such that the S-polarized light and the p-polarized light included in the measurement light entering the surface of the substrate have the same strength. The surface shape measuring device according to claim 2, wherein the illumination system comprises at least one of a polarizer and a phase plate, the polarization adjusting unit comprises a driving unit, The system is configured to rotate at least one of the polarizer and the phase plate and to adjust the intensity ratio by rotating the polarizer and at least one of the phase plates with the drive unit. 4. A surface shape measuring device configured to measure a surface shape of a film formed on a substrate, the apparatus comprising: an illumination system configured to split a broad band of light from a source Forming the measurement light and the reference light, the measurement light is irradiated to obliquely enter a surface of the film, the reference light is irradiated to obliquely enter a reference mirror t-light receiving system, configured to be made by the film The measurement light reflected by the surface and the reference light reflected by the reference mirror are combined with each other, and the combined light is guided to a photoelectric conversion element; and a processing unit is configured to Calculating the surface shape of the film by an interference signal detected by the photoelectric conversion element, wherein an incident angle of the measurement light on the surface of the film and an incident angle of the reference light of the reference mirror Both are greater than the Brewster angle, and the illumination system includes a first polarizer that allows linearly polarized light in a predetermined direction to pass, the linearly polarized light system being included in the broadband light from the light source, And the light receiving system includes a second polarizer that allows linearly polarized light in the predetermined direction to pass, the linearly polarized light system including the measurement reflected by the surface of the film - 44- 200947142 The linearly polarized light in the predetermined direction, including s polarization, in at least one of light, the amount of light reflected by a surface of the substrate, and the reference light reflected by the reference mirror Light and P pole - light. 5. The surface shape measuring device according to claim 4, wherein the predetermined direction is a +45 direction or a -45 direction. 〇6. A surface shape measuring device configured to measure a surface shape of a film formed on a substrate, the apparatus comprising: an illumination system configured to light a broadband band from a light source Splitting into measuring light and reference light, the measuring light is irradiated to obliquely enter a surface of the film, the reference light is irradiated to obliquely enter a reference mirror t-light receiving system, configured to The light meter reflected by the surface of the film and the reference light reflected by the reference mirror are combined with each other, and the combined light is guided to a photoelectric conversion element; and a processing unit is configured to Calculating the surface shape of the film by an interference signal detected by the photoelectric conversion element, wherein an incident angle of the measurement light on the surface of the film and a reference light of the reference mirror Each of the incident angles is greater than a Brewster angle, and the illumination system includes a first polarizer and a first wavelength plate, the first polarizer allowing linearly polarized light in a predetermined direction to pass, the linear polarization Included in the broadband light from the light source, and the first wavelength plate allows light that has passed through the first polarizer to pass, and -45-200947142 the light receiving system includes a second wavelength plate, allowing Passing linearly polarized light of the predetermined direction, the linearly polarized light system comprising the metering light reflected by the surface of the film, the metering light reflected by a surface of the substrate, and The surface shape measuring device according to claim 6, wherein the light receiving system comprises a second polarizer, allowing the present invention to be present in at least one of the reference light reflected by the reference mirror. The linearly polarized light of the predetermined direction passes, and the linearly polarized light is included in the light that has passed through the second wavelength plate. 8. The surface shape measuring device according to claim 6, wherein the first wavelength plate is a λ/4-plate. 9. The surface shape measuring apparatus according to claim 1, wherein the refractive index of the reference mirror associated with the broadband light from the light source is not less than 1.4 but less than 2.5. 10. An exposure apparatus configured to expose a substrate through a pattern on an original plate, the exposure apparatus comprising the surface shape measuring apparatus according to any one of claims 1 to 9. 11. An exposure apparatus configured to expose a substrate through a pattern on an original plate, the exposure apparatus comprising: a first surface shape measuring unit configured to obliquely enter by illuminating light Measuring a surface shape of the film formed on the substrate by detecting a surface of a film and detecting a position of the reflected light from the surface of the film; and according to claims 1 to 9 of the patent application Any of the surface shape quantities -46 - 200947142, as a second surface shape measuring unit, the result of measuring one of the first surface measuring units is measured based on one of the second surface measuring units The result is corrected. 12. A device manufacturing method comprising: exposing a substrate by using an exposure apparatus according to claim 10; and developing the exposed substrate. -47-